Memory device and preparation method thereof

The present application discloses a memory device and a preparation method thereof. The memory device includes a first chip and a second chip. The first chip includes a first storage array and a second storage array. The first storage array includes at least one first storage block. The first storage block includes a plurality of first word lines extending in a first direction and a plurality of first bit lines extending in a second direction. The second storage array includes at least one second storage block. By constructing a first global bit line sub-decoder block in a first overhead projection area formed by the first storage block and constructing a second global bit line sub-decoder block in a second overhead projection area formed by the second storage block, an occupied area of the first chip and the second chip after stacking can be reduced, which reduces an occupied area of the memory device and is beneficial for minimizing a size of the memory device.